"These wildfires, when they become wind-driven, are like a nuclear bomb going off, and humans are not going to stop them any more than they stopped the hurricanes in Gulf Coast," Dr. Steven Running of the University of Montana said this morning on a conference call about climate change, heat waves and wildfires.

The conference call was hosted by Climate Communication, a nonprofit science and outreach project connected with the Colorado-based Aspen Global Change Institute. Climate Communication has released a summary of the latest research that shows the number of heat waves worldwide is increasing. In the United States, new record-high temperatures outnumber new record-low temperatures by two-to-one.

"What we're seeing is a window into what global warming looks like," said Dr. Michael Oppenheimer of Princeton University, one of three scientists on the call. "It looks like extreme heat. It looks like fires. It looks like this type of environmental disaster."

"What scares firefighters is there's still two or three months of summer to go," Running added. "When we have fires this wild early in the summer, it's of very high concern."

Scientists hesitated to put a percentage on the impact of climate change on wildfires. Hotter temperatures lead to more evaporation, they said, which leads to drier forests. As those hotter temperatures start earlier and last longer, the wildfire season grows, too. And when temperatures stay high at night, it allows the fires to burn 24 hours a day.

Running also pointed out that climate change leads to warmer winters, which means pine beetle larvae are able to survive the cold. "That means those beetle populations wake up in the spring and can start the attack that much sooner and that much more aggressively, which provides that many more dead trees," he said -- which are fuel for the fire.

"As they say out here," Running added, "the rodeo is on."

Dr. Howard Frumkin of the University of Washington warned that wildfires are bad for human health. The smoke from the fires is "very, very similar to severe air pollution," he said. "Using particles (in the air) as an indicator, the pollution levels can reach as high as several times higher than a bad day in Mexico City or Beijing."

Wildfires also take a toll on people's mental health. Evacuating one's home because of a wildfire is "emotionally stressful," Frumkin said. Evacuees -- such as the estimated 32,000 displaced by the Waldo Canyon fire -- often suffer from post-traumatic stress disorder, anxiety and depression, which Frumkin categorized as "serious public health concerns."

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